Follicle tracking is a common fertility procedure, it involves tracking the development of egg-containing follicles within your ovary from an immature state (which we call primordial follicles) to a mature state (we call leading or dominant follicles).
Knowing when your eggs are nearing maturity helps to know when ovulation occurs and also predicts the best time for IVF clinicians to perform an egg pick up.
Follicle tracking is done via an internal (transvaginal) ultrasound in combination with monitoring your blood levels for the female hormones oestrogen and progesterone.
The procedure only takes about 10 minutes, you will be asked to empty your bladder prior to the scan, upon arrival at the clinic. When you enter the ultrasound room you will be asked to remove your underwear and either put on a gown or be covered with a sheet and lying down on the bed with your feet on a lower platform. With your consent, the small narrow sterilised transvaginal transducer is gently placed a small way into the vagina The probe is moved from side to side to gain views of the ovaries and count the follicles on each. The sonographer may need to gently push on your lower abdomen with her other hand to displace overlying bowel gas. For more information on this procedure please read: the transvaginal information sheet.
Tracking for timed intercourse
Follicles may be tracked in a natural cycle. When a leading follicle is seen (average size 22 mm, with a range of 17-27mm) then intercourse may be appropriately timed. Alternatively, drugs which promote release of the mature egg (luteinising hormone) may be administered.
Tracking for IVF
For most IVF treatments, your ovaries will be artificially stimulated with follicle stimulating hormone (FSH) which produces multiple mature follicles which are then harvested following administration of luteinising hormone (LH). In this setting, your follicular development is followed more closely with 2 to 4 ultrasound scans, and regular blood sampling to track your hormone levels. The timing of your egg collection is based on the ultrasound and your blood results. This information will be provided to you by your IVF nurse or clinician.
Egg collection is performed as a transvaginal ultrasound guided procedure under anaesthetic by the IVF specialist. However, in some patients if there is difficulty achieving vaginal access, egg collection may be performed transabdominally.
At Sydney Ultrasound for Women, we provide ultrasound services for many IVF patients.
IVF clinicians and nurses work closely with our sonologists and sonographers to ensure accurate, timely results that give you the best chance of IVF success.
